Heating furnace



July?, 1929v G. E. EVANS ET AL 1,719,466 l HEATING FURNACE Filed'June 20 1927 2 sheets-sheet 1 In@ ons t? 5MM,

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July 2, 1929- G. E. EVANS ET Al.

HEAT ING FURNACE Filed June 2oi 1,927 2 sheets-sheet Patented July 2, 1929.

UNITED STATES PATENT OFFICE.

GEORGE E. EVANS AND WILLIAM F. EVANS, OF IVIOLINE, ILLINOIS, ASSIGNORS T0 THE GEORGE EVANS CORPORATION, OF MOLINE, ILLINOIS, A CORPORATION 0F ILLI- N OIS.

HEATING FURNACE.

Application filed June 20,

The present invention relates to heating furnaces and has particular reference to hot air 'furnaces of the type employed for household heating, although the novel features of the invention may be` embodied in other types of heating units, such, for example, as in industrial furnaces for heating gases etc.

The principal aim of the invention is to provide a heating furnace wherein the heating passages are built up of sheet metal sections of improved form and construction. By virtue of these sheet metal sections the area of heat transfer surface for a given size of furnace is greatly increased; the walls through which this heat transfer is effected are of relatively small sectional thickness, so that the furnace is quickly brought up to heating temperature; the alternate expansions and contractions of the heating sections are readily accommodated by the flexibility of the sheet metal walls, which is of particular advantage when the furnace is being fired by an intermittently operating oil burner; and the entire furnace is made relatively light in weight, and is produced at low cost.

Referring to the accompanying drawings wherein we have illustrated a preferred embodiment of our invention:

Figure 1 is a vertical longitudinal sectional view through the furnace,

Fig. 2 is a horizontal view, partly in elevation and partly in section, showing the arrangement of the heating sections.

Fig. 3 is a vertical transverse sectional view taken on the plane of the line 33 of Figure 1.

Fig. 4 is a fragmentary perspective view' of one of the sections.

Fig. 5 is a fragmentary sectional view illustrating the manner of connecting the ends of the sections, and

Fig. (S is a detail sectional view illustrating a modified construction.

The furnace is preferably of rectangular form` and is enclosed in a housing 10 which may be suitably insulated against heat loss. This housing may be of unitary construction, or it may be sectionalized into a plurality of walls or panels adapted to be joined together. In the construction shown, the front and rear walls 11-11 and the end walls 12 are formed as an integral rectangular shell. The top of such shell is open, and is adapted to be closed by a removable cover 1927. Serial No. 199,919.

plate 13 which is bolted to the flanged upper edge of the shell 10. Rising from the cover plate 13 is a hot air manifold 14, which may consist of a suitable sheet metal housing or shell secured to an upwardly extending flange 15 projecting from the cover plate 13. Branching from the top of the manifold 14 are one or more hot air conduits 1G which serve to conduct the heated air to different parts of the house or building.

Extending transversely of the furnace, intermediate the ends thereof, is a fire box 17. Such fire box preferably extends down substantially to the floor, and the lower portion thereof is defined between side walls 18 composed of fire brick, or fire clay reinforced by side plates 19. The upper portion of such fire box or combustion chamber is defined between the ends of right and left banks of heating sections 21 which extend laterally from this combustion chamber toward the ends of the furnace. The top of the chamber is closed off from the hot air manifold 14 by a plate 22 which is secured to the tops of the sections and extends the full length of the chamber. Provision may be made for burning coal, oil, or gas in the fire box, the conduit 23 entering the front end thereof being representative of an oil burner conduit. It is opportune to remark at this point that the construction shown is what we regard as a large or double unit, characterized by an intermediately located fire box having heat-- ing sections extending laterally from each side thereof, but if desired, smaller units can be constructed with a single bank of sections extending from the end or side of the fire box.

The products of combustion pass laterally in each direction through the banks of sections 21--21 towards the ends of the furnace. In their passage through these sections, the products of combustion are caused to flow through tortuous or sinuated passages which lie in immediate proximity to vertically extending air passages for effecting an etlicient transfer of heat, all of which will appear in the subsequent description of the sections. The products of combustion issue from the ends of the sections into discharge chambers 24 defined between the end walls of the housing and the faces of the banks of sections 21-21. The tops of both of said chambers are closed by the cover plate 13, and the bottoms thereof are closed by plate portions Q5 extending inwardly from the furnace housing at a point .spaced upwardly from the bottom of the housing. The areas defined below these inwardly extending plate portions 25, and below the bottoms of the sections 2l, constitute cold air chambers 2G where the air is admitted to the furnace for passing up between the heating sections. Formed in each of the plate portions -25 are elongated openings 27 which communicate with exhaust eonduits28. The latter convey the exhaust gases to a stack conduit 2f) which may extend from the back or ends of the furnace, as desired. In the arrangement shown, said stack conduit extends upwardly from thc rear wall ll of the furnace htaising and the two conduits 2S extend di agonally back to such rear wall where the)Y both open into the stack conduit. At the point where the conduits 2S pass out through the housing. an inclined protecting wall 2t) of fire clay or brick is built up to cover the conduits 28 and protect them from the burner flame. The air to be heated is a1lmitted to the lower chamber areas QG through openings 3l formed in one of the walls of the housing, such as the rear wall, and these openings may communicate with a. manifold or conduits leading to any point from which it is desired to draw the air.

The plate portions 25 form parts of open frame structures which support the heating sections 21 above the air chambers 26. Such frames may be cast in unitary form 0r may consist of suitable angle bars 32 and 33 secured to the front and rear walls of the housing and to the side plates 1t) of the fire box.

Referring now to the manner of constructing the heating sections, it will be observed from Fig. et that each section is composed ot'Y two sheet metal side walls 34 and 31". Although we find it preferable to make these two side walls from separate sheets, as by joining the edges oll these sheets along the upper and lower edges of the section, it will be luider-stood that such side walls might consist ot two halves of a single sheet folded along a median line. Prior to the joining of the edges of such sheets, eorrugations or indentations are formed therein to produce alternating peaks 35 and valleys 36. Such corrugations or indentations may be formed in the plates either by rolling, stamping, or in any other preferred manner, and may be of V-shaped cross section as shown, or of gradually rounded curvature, although we find the approximate sectional formation shown to be preferred for best. results. The corrugations extend crosswise of the sheets, so that they will bc disposed vertically in the finished section, and the upper and lower ends of each corrugation terminate short of the edges of the plate, merging on gradually rounded curves 37 into thc plane of the sheet. rl'he flat edge portions lying beyond the corrugations along' the upper and lower edges of the plate constitute joining flanges 38 and 38h. Said flanges are preferably joined together by welding', performed either by an Oxy-acetylene flame, or electrically, the weld being indicated at It will be observed from Fig. 5 that in the finished section the peaks 35 of one plate match with the valleys 3G of the opposite plate, and that these peak and valley portions are spaced from each other to define a zig-Zag or sinuated passageway slt of substantially uniform cross-sectional area extending throughout thc entire length of the section. Such passageway constitutes a flue duct for conducting' the hot gases through the heating section, opening at one end into the combustion chamber 1T and at the other end into the exhaust chamber 24.

The sections thus formed are grouped in banks or nests, so arranged as to define vta'tically extending air passages 42 extending up between adjacent sections. Preferably the sections are so arranged that the peak portions 353 of one section contact with or lie in immediate proximity to the peak portions of the next adjacent section. In such arrangement the air passages 4Q are defined between the matching valley portions of adjacent sections and hence are of .square or diamond shaped cross section, depending upon the specific form of the corrugations. Thilo this is the preferred arrangement, it will be evident that the sections might be grouped with the peak portions 35 of one section uiatching with the ralley portions 36 ot' the next adjacent section. but spaced therefrom so that the upwardly extending air passage 4Q would be in tue shape of a continuous passage of sinuated form extending' throughout the length of the bank of sections.

The end faces of each bank of sections aril closed ofl` in the manner shown in Fig. 5, or in accordance with the modified eon struction shown in Fig. 6, whereby the air spaces between adjacent sections are sealed from the ends of the sections, leaving only the flue passages 4l opening outwardly from the ends of the sections. It will be observed that when the sections are grouped with the peaks of one section lying opposite the peaks of the next adjacent section, the flue passages Al1 of two of these sections will open from the end of the bank in immediate proximity to each other, and the flue passages of the next two sections will open from the end of the bank, also in immediate proximity to each other, but spaced from the first pair of flue passages bv the width of one of the air passages 4Q. rl`he opposite walls 34a-3ft" of the first mentioned pair of sections contact back to back at the end and are welded together along` contacting portions, as indicated at 44. The intervening space between this pair of adjacent flue passages and the pair of the next; adjacent flue passages is sealed by a closure flange 45 which is bent at right angles to one of the sections to extend over and engage with the opposite Yall of the next adjacent section. The edge of this flange is welded to the contacting edge of the latter section along the line indicated at 4G. The above described manner of joining adjacent sections is continued across the entire end face of the bank, and is duplicated at the other ends ot'V the sections. Thus, while the sinuated flue passages are open at the ends of the sections, the air spaces intermediate the sections are closed oft' from said ends.

In the modified construction shown in Fig. G, the intervening space between pairs of flue passages is closed by extending two flanges 1,17*/17 from each of the adjacent sections at this point, and bending the edges of said flanges forwardly for welding along the line 4S.

After the sections have been joined together in the manner described, the two banks thereof are placed within the housing 1t), where they rest on the frame bars 25, 32 and 33. The lower edges of each bank may be suitably secured to said frame bars to form an air-tight closure between the edges of the bank or group of sections and said bars. The front and rear sections of each bank are also joined to the front and rear walls of the housing. One manner of accomplishing this is to bend the projectiing flange portions 45 of such front and rear sections at a right angle, as indicated at 45, and securing said bent portions to the housing. lVhere these flanges 45 do not occur' between the outermost sections and the housing. suitable angle strips, similar to the bent portions 45', may be secured to said sections and to the housing. For closing olf the openings which occur at the upper and lower edges of the sections at the points where the corru,\,'ations Btl curve back into the planes of' their resj'icctive sheets, wc provide closure members in the form of angle bars or plates 51 which extend across the ends of cach group of sections at the upper and lower edges thereof. These closure members are preferably welded to they edges of the sections and to the closure flanges l5 so as to seal the air spaces at the upper and lower edges of the sections.

lt will be .seen from the foregoing that the products ot' combustion will pass laterally in each direction from the combustion chamber 17 through the horizontalltv extending liuc passages 4l of the sections and will discharge into the end chambers 24. From these chambers the spent gases are of the bank their entire conducted downwardly through the conduits 28 to the stack 2%), this providing in effect a down draft for the flue gases. The relatively cold air entering the lower chambers 2G will upwardly through the air passages 42 between adjacent sections, where such air will be heated, the same then discharging into the manifold 1% for passage through ythe conduits 16 to the different, parts of the house. The multiplicity of flue passages 41 and air passages 4t2 afford an extensive area of heat exchange surfaces, tending to a high efficiency of the furnace. \Vliatte\'er temperatures are present in the exhaust gases being conducted through the conduits 28 are also cfl'ective for heating the air in the lower air chambers 2G. Obviously the sheet metal sections possess an inherent flexibility which accommodates a wide range of expansion and contraction.

White the construction above described embodies what we consider to be the preferred t'orm of the invention, it will be understood that such is merely exemj'ilary, and that dift'eent changes and rearrangements may be made therein without departing from the invention.

lVhat we claim as our invention and dcsire to secure by Letters Patent, is-

1. A heating furnace having a heating section comprising pairs of spaced parallel walls, said walls being formed of similar corrugated plates with the corrugations of one plate extending in the same direction as the coirugationsI of the other plate, thereby defining a passage through which the gases advance in a sheet of uniform cross section, the adjacent pairs-of walls being spaced to form a plurality of noncommunicating air passages between them.

2. A heating furnace having two groups of heating sections extending laterally from opposite sides of a fire box, cach ol' said sections comprising a plurality ot' pairs of corrugated metal plates with the corrugations of' one plate parallel to the corrugations of the other plate, thereby defining a passage through which the gases advance in a sheet of uniform cross section, said pairs of corrugated plates defining sinuous lateral flue passages interiorly, noncommunicating air passages exteriorly, means for admitting hot of combustion to said lateral passages from said fire box, and means for admitting air to be heated at the bottom of said air passages.

3. A heating furnace comprising a fire box. a group of heating sections. each of said sections comjn'ising a pair oll spaced similarly corrugated plates a uniform distance apart throughout the entire areas of the plates, said corrugations being placed so as to define a sinuous flue passage within parallel curved walls, said sections being spaced with respect to each other to define air passages, said lirst passage having openings for erfnduetion of the hot gases of combustion, and said second passage having openings for admit-asien of air to he heated.

4. A heating furnace Comprising a heating section formed ol" a pluralityv of similarly corrugated metal plates, pairs ot' said plates defining similar sinuous flue passages. said passages having a uniform rross-seetion throughout said walls exleriorly delining a plurality of non-communieating air passages. means Yfor admitting the hot gases ot' vomliustion to said iue passages, means for admitting air to he heated to said air passages. the ends of said eorrugations iermioaling short ol' eaeh plate to form joining flanges alongr the edges of said plates, said flanges ontaetiug with eai'h other and heing welded together7 interveniiig members between said lateral passages to prevent passage oi' flue gases into the air passages, and means lor joining said intervening men'iherf's to said metal plates.

5. In an air heating furnace, a plurality of spaced pairs of Corrugated plates, each pair delining a flue passageway, the plates of adjacent pairs defining a llue passageway eX- tending at right angles to the first mentioned flue passageway, means for passing gases of Combustion through one ot' said passageways, and means for passing air through the other passageway.

(i. In an air heating furnace(` a plurality of spaced pairs of corrugated plates, each pair defining a Hue passageway of uniform Cross sectional area, the plates of adjacent pairs being joined together to define a pluraliiy of spaced parallel passageways, eX- tending at right angles to the lirst mentioned flue passageway, means for passing gases of combustion through one of said passageways, and means for passing air through the other passageway.

GEORGE E. EVANS. WILLIAM F. EVANS. 

